There really isn't much of a need for a rule for adjusting damage bonuses. I think a much better solution for custom servers would be a rule for adjusting the main damage multipliers. So you would increase or decrease normal damage instead of messing with damage bonuses. This is something that I think KLS has already considered adding at some point.
Also, along with that rule it would be nice to have an additional one for adjusting how often hits land for PCs and/or NPCs. Both of these would just add an additional multiplier to the equations that calculate them. Then if the rules are set to 100, it would mean no adjustment, 50 would be half and 200 would be double, etc.
Whether those rules get added or not isn't really related to this thread though and should probably be discussed elsewhere IMO. I am pretty sure there is already a thread somewhere talking about them.
Actually, while thinking about these 2 rules, it made me think of a cool new idea for a quest command. Maybe additionally to these rules, a quest command could be made that would adjust the entire zone damage and hit rates on the fly for all NPCs in it. Then, you could make zones that automatically scale in difficultly based on player level. Though, another rule to scale hps would probably help too
